Torque Resistant Terminal Block Element

ABSTRACT

A screw terminal and a terminal block incorporating the same provides a mechanically a screw terminal frame with a closed perimeter that resists deformation of the terminal frame when a captured nut is being clamped against a wire within the terminal frame, allowing the captured nut to be clamped more tightly against the wire. Sidewalls of the terminal frame may include tabs that engage ledges of a block housing to support the screw terminal and the captured nut may have surface irregularities upon the surface that engages the wire and to improve electrical contact therebetween and resist mechanical pull out of the wire.

CROSS REFERENCE TO RELATED APPLICATION

This Non-Provisional Application claims benefit to U.S. Provisional61/254,092 filed Oct. 22, 2009 and hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to electrical terminalsproviding a releasable mechanical and electrical connection to acurrent-carrying wire and, in particular, to a screw terminal in whichthe connection is made by tightening a machine screw.

BACKGROUND OF THE INVENTION

Electrical screw terminals, normally as part of a terminal block,provide a versatile and reliable method of making electricalconnections. The quality of the connection to a screw terminal, both interms of providing low electrical resistance and high mechanicalstability, is increased by increasing the clamping force of the nut onthe wire. Increased clamping force may be obtained by applying greatertorque to the machine screw. However, known screw terminals and terminalblocks are limited with respect to how much screw tightening torque theycan accept and are correspondingly limited with respect to how muchclamping force the screw terminals can apply to a wire.

In a simple terminal block, each screw terminal includes an electricallyconductive machine screw which is threadably received by the terminalbody. The wire to be connected is captured under the head of the machinescrew as the machine screw is tightened.

In these simple terminal blocks, tightening the screw beyond a certainextent can squeeze the wire at least partially out from under the screwhead. For multi-strand wires, this may reduce the number of strands thatare mechanically held by the screw and compromise the electricalconnection between the wire and screw terminal. For single-strand wires,this may completely remove the wire from its connection with the screwterminal, requiring an installer to loosen the screw and start over withconnecting the wire to the terminal.

More sophisticated screw terminals employ enclosed channels into whichthe wire may be inserted to be captured between one wall (a clampingwall) of the channel and a threaded nut within the channel. Multipleterminals of this type may be held in an electrically insulating housinghaving barrier walls between terminals to form a terminal block. The nutmay be guided by flanking walls of the channel to prevent its rotationas the machine screw is loosened or tightened. The channel may provide alip opposite the clamping wall to retain the nut on the machine screwwhen the nut is loosened.

All such potential issues associated with existing screw terminals cancompromise the clamping force that is applied to the wires andcorrespondingly compromise the integrity of the electrical connection.This can lead to device malfunction that may require field service callsby technicians to resolve and/or other downsides.

SUMMARY OF THE INVENTION

The present inventor has recognized that in channel-type screwterminals, tightening the screw beyond a certain extent can force thenut to rotate within the channel and push out the channel walls, awayfrom each other. This distorts the channel which may loosen theconnection between the screw terminal and the terminal housing. When thenut rotates in the channel, it is turning in unison with the screw,whereby it is not further advancing along the screw and not increasingthe clamping force on the wire.

The inventor has also recognized that in such channel-type screwterminals, standard nuts are used which may be relatively thin in somescrew terminals. Thin or short nuts have relatively few threads so thattightening the screw beyond a certain extent may strip the threads fromthe nut, rendering the screw terminal unusable.

Furthermore, the inventor has recognized that terminal blocks havingchannel-type screw terminals which require the nuts to be pulled uptoward the screw head can be difficult to visually differentiate fromthose having screw terminals that require the nuts to be pushed awayfrom the screw head. That is because many terminal blocks have smallwindows through which the wires are inserted into the screw terminals,while the particular mechanical configurations of the nuts, screws, andchannels of the screw terminals are mostly covered by terminal blocks.Correspondingly, at times, assemblers mistakenly place wires underneathnuts in channel-type screw terminals, so that the wires get pinchedbetween the nuts and the window perimeter edges instead of the nuts andthe respective clamping walls.

The present inventor has developed screw terminals and correspondingterminal blocks that can apply larger clamping forces to wires whileavoiding numerous problems that have previously been associated withtrying to apply higher torques to the screws. The particularconfiguration(s) of the screw terminal and terminal block allow themachine screws to be tightened more than could previously be done,without compromising the interaction of the nut, the screw, and theclamping wall.

Specifically, the present invention provides an electrical screwterminal that includes a blade for connecting the electrical screwterminal to a receptacle that is provided in an electrical circuit. Aterminal frame is connected to the blade and has a closed perimeter withan inner space defined within the closed perimeter. The inner space ofthe terminal frame houses a captured nut that moves along a screw whenthe screw is rotated. The closed perimeter of the terminal framedefined, at least in part by an upper wall, a pair of side wallsextending from the upper wall, and a base wall extending between andconnecting the side walls to each other at their lower ends.

It is thus one object of the invention to provide an electrical screwterminal of simple construction with a closed perimeter terminal framethat anchors its side walls together at their upper and lower ends,mitigating the extent to which a captured nut can within the terminalframe and push the side walls away from each other. This may increasehow much clamping force the captured nut applies to a wire becauserotation of the screw is substantially converted into linear movement ofthe captured nut along the screw. Therefore, the captured nut may movealong the length of the screw in preference to rotating the captured nutand bending out the sidewalls of the terminal frame.

The base wall may include (i) an upright base wall portion that extendsgenerally parallel to the side walls, and (ii) an angled base wallportion that extends generally angularly with respect to the side walls.The terminal frame may include a pair of lips extending from the sidewalls toward each other and connecting the side walls to the upright andangled base wall portions of the terminal frame.

It is thus another object of the invention to provide an electricalscrew terminal with multiple base wall portions, at least one of whichextends angularly with respect to the side walls. The angled base wallportion may serve as an angled gusset or brace that adds rigidity to theterminal frame. The pair of lips connects the side and base wallportions to each other, which may further add to the rigidity of theterminal frame. The rigidity of the terminal frame may help hold theside walls a constant distance from each other, ensuring that thesidewalls do not bend out to accommodate rotation of the captured nut,and resist folding, buckling over, or collapsing of the terminal frame.This may allow greater downward pressure and torque to be applied to thescrew while installing a wire into the screw terminal, increasing theamount of clamping force applied to the wire.

The terminal frame may also include a finger extending between andfixing the upright and angled base wall portions with respect to eachother, anchoring the side walls at a constant distance with respect toeach other. An aperture may extend through at least one of the blade andthe upright base wall portion and the finger may extend through theaperture. An end of the finger may be bent to define a J-shaped profilewith the bent end pointing upward toward the terminal frame.

It is thus another object of the invention to provide an electricalscrew terminal with upright and angled base wall portions that aremechanically attached to each other or to other components or portionsof the screw terminal. This may prevent relative sliding movement andbending of portions of the screw terminal with respect to each other andmay maintain the integrity of the terminal frame so that the side wallsof the frame do not bend outwardly and thus may also mitigate tendenciesof the captured nut to rotate between the side walls.

The captured nut may include a top wall with an irregular surface. Theirregular surface of the captured nut top wall may include multipleridges. The ridges may extend in a direction that is generallyorthogonal to the wire that is held in the screw terminal.

It is thus another object of the invention to provide an electricalscrew terminal with a capture nut that includes ridges, grooves, orother surface irregularities that can engage or bite into the wire. Thisconfiguration increases the surface area of the interface of thecaptured nut and wire and may supplement the holding ability of thescrew terminal so that a greater pulling force would be required towithdraw the wire from the screw terminal.

The electrical screw terminal may be provided within a terminal blockthat includes a housing which is made from an insulating material thatat least partially covers the electrical screw terminal. The housing ofthe terminal block includes an opening that aligns with the inner spaceof the terminal frame. The captured nut is movable between (i) an openposition in which a passage extends through the opening of the housingand into the inner space of the terminal frame, allowing the wire toinsert through the housing and into the terminal frame, and (ii) aclosed position in which the captured nut extends across substantiallythe entire opening of the housing, preventing the wire from insertinginto the terminal frame.

It is thus another object of the invention to provide a terminal blockwith a captured nut that is tall enough to substantially cover theopening through the housing when the captured nut is tightened without awire in the screw terminal. This may ensure that the wire is inserted onthe appropriate side of the nut and the relatively taller nut may havemore threads that can accommodate greater forces in its threadengagement with the screw, allowing the nut to apply greater clampingforces to the wire.

The housing may include a top wall that retains the screw from above.The housing may also include a ledge that supports the screw terminal byan engagement of a tab that extends from the terminal frame and theledge. The screw terminal is vertically maintained within the housing,between the housing top wall, and the ledge.

It is thus another object of the invention to provide a terminal blockthat can prevent the screw from being completely removed from thecapture nut. It is another object of the invention to provide a terminalblock with a robust support that can hold the screw terminal in avertical direction, allowing move downward force to be applied to thescrew when rotating it, which may result in more torque being applied tothe screw without the tool slipping out of the screw.

Other features and advantages of the invention will become apparent tothose skilled in the art upon review of the following detaileddescription, claims, and drawings in which like numerals are used todesignate like features.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a terminal block of the presentinvention;

FIG. 2 is an enlarged pictorial and exploded view of a portion of theterminal block of FIG. 1 cross-section along line 2-2 in FIG. 1;

FIG. 3 is a sectional view of the terminal block of FIG. 1 takengenerally in the plane indicated by line 3-3 in FIG. 1; and

FIG. 4 is a perspective view of a captured nut of the terminal block ofFIG. 1.

Before the embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of the components setforth in the following description or illustrated in the drawings. Theinvention is capable of other embodiments and of being practiced orbeing carried out in various ways. Also, it is to be understood that thephraseology and terminology used herein are for the purpose ofdescription and should not be regarded as limiting. The use of“including” and “comprising” and variations thereof is meant toencompass the items listed thereafter and equivalents thereof as well asadditional items and equivalents thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 each shows a terminal block 5 or portion thereof that isconfigured for electrically connecting wires 8 to a receptacle 6 in anelectronic device or system. Terminal block 5 includes a housing 10which holds at least one screw terminal 100. As shown in FIG. 2, eachscrew terminal 100 includes a generally box-shaped frame 110 from whicha conductive blade 130 extends and that has open ends and an inner spacethat holds a captured nut 160 that is movable along a screw 150,explained in greater detail elsewhere herein.

Referring now to FIG. 1, this particular embodiment of housing 10 holdsthree screw terminals 100. The three illustrated screw terminals 100 areprovided to connect wires 8 to the line “L”, neutral “N”, and ground “G”conductors of an electrical circuit(s). This configuration can be usedwith, for example, circuits carrying about 20 A at about 300V, orothers, based on the particular end-use configuration of the electronicdevice or system.

Still referring to FIG. 1, the housing 10 of block 5 is made from aninsulating material and at least partially covers each of the electricalscrew terminals 100, which are made from a suitably electricallyconductive metallic material(s). Only blades 130 and screws 150 arereadily accessible from outside of the housing 10. Blades 130 insertinto conductive sockets of the receptacle 6 that are part of thecorresponding electrical circuit(s) to connect the screw terminals 100and thus also terminal block 5 to the end use device or system.

Referring yet further to FIG. 1, the illustrated housing 10 includescylindrical screw bosses at its ends. Mounting screws extend through tosecure the block 5 to the receptacle 6. The front of housing 10 includesflexible tabs that interlock with or snap-fit into correspondingstructures of the receptacle 6, which helps hold the block 5 to thereceptacle 6. A release lever is provided by one of the flexible tabsthat facilitates removal of the block 5 from the receptacle 6. Portionsof the housing 10 that hold the screw terminals 100 are spaced from eachother by parallel and upright support webs.

Referring now to FIG. 3, the respective portions of the housing 10 thatconfine the screw terminals 100 each includes a top wall 12 thatoverlies the respective screw terminal 100, so as to prevent removal ofthe screw terminal 100 from the top of the block 5. In this embodiment,top wall 12 has a hole through which part of the head of screw 150extends. A flange that radiates from the bottom of the screw 150 headnests inside of a curved undercut in the bottom of the top wall 12. FIG.2 shows the undercut as a step at the bottom of the curved back edge ofthe opening in top wall 12. Preferably, the top wall 12 retains thescrew 150 within the housing 10 so that when the nut 160 is pushed allthe way down toward the blade 130, the screw 150 still extends into thenut 160. In this configuration, the screw 150 cannot be fully removedfrom the nut 160 when the screw terminal 100 is mounted in the housing10.

Still referring to FIG. 3, each portion of the housing 10 that confinesa screw terminal 100 includes a pair of walls 14, 15 that extend downfrom the top wall 12, covering most of the length of the screw terminal100. Ledges 16, 17 extend inwardly from the walls 14, toward each otherand into a void space of the housing 10 in which the screw terminal 100sits. Ledges 16 and 17 have ramped lower surfaces that facilitateinsertion of the screw terminal 100 through an opening at the bottom ofthe housing 10. The ledges 16, 17 include flat top surfaces that serveas shoulders against which the screw terminal 100 is supported in avertical direction, described in greater detail elsewhere herein.

Referring again to FIGS. 1 and 2, openings 18 extend through a forwardfacing wall of the housing 10. The openings 18 are aligned withcorresponding openings that extend into the terminal frames 110 of thescrew terminals 100. This allows wires 8 to be inserted into andconnected to the screw terminals 100 by way of the screws 150, nuts 160,and terminal frames 110.

Referring now to FIGS. 2 and 3, the terminal frame 110 of screw terminal100 includes a flat upper wall 112 that abuts the bottom surface of topwall 12 of the housing. Upper wall 112 has a hole through which thetreaded shaft of screw 150 extends. In this embodiment, the hole inupper wall 112 is slightly off-center, as is the longitudinal axis ofscrew 150, with respect to the upper wall 112.

Still referring to FIGS. 2 and 3, a pair of side walls 114, 115 extendsdownwardly from opposing sides of the upper wall 112. The side walls114, 115 have tabs 116, 117 that extend outwardly to engage the ledges16, 17 of the housing walls 14, 15 (FIG. 3). In this embodiment, thetabs extend angularly out and down from upper portions of the side walls114, 115. This allows the tabs to deflect inwardly and slide over thelower surface ramps of the ledges 16, 17 when the screw terminal 100 isinserted into the housing 10 through the open bottom wall of the housing10. Tabs 116, 117 are sufficiently resilient to snap out against thehousing walls 14, 15 after the tabs 116, 117 have slid past the ledges16, 17 during insertion. Accordingly, once the screw terminal 100 isinstalled in the housing 10, the screw terminal 100 is verticallycaptured between the housing upper wall 12 and the ledges 16, 17. Theledges 16, 17 provide mechanical stops against which the tabs 116, 117wedge and sit so that downward forces applied to the screw 150 aretransferred through the tabs 116, 117 into and through the ledges 16, 17and thus into the housing walls 14, 15 distributing such forces throughthe housing 10.

Still referring to FIGS. 2 and 3, the overall configuration of theterminal frame 110 helps ensure that the screw terminal 100 hassufficient structural integrity to transfer such loads. The generallybox-shaped configuration that defines a closed perimeter of the terminalframe 110 holds the side walls 114, 115 in a constant position whichprevents the nut 160 from rotating between them. In this way, theterminal frame 110 resists the input torque being to the screw 150 andnut 160, which forces the nut 160 to move linearly along the screw 150instead of rotating. Holding the side walls 114, 115 in constantpositions also holds the tabs 116, 117 in their proper positions forengaging and being supported by ledges 16, 17.

Referring yet further to FIGS. 2 and 3, lips 120, 121 extend from thebottoms of side walls 114, 115, respectively, toward each other. Lips120, 121 support the nut 160 from below when the nut 160 is at itsbottom position or at the downward travel limit, blocking furtherdownward travel of the nut 160, as shown in FIG. 2. In this embodiment,lip 121 extends about three times further or is about three times widerthan lip 120. The end of lip 121 that is furthest from side wall 115sits under the threaded shaft of the screw 150, whereas the end of lip120 that is furthest from side wall 114 sits approximately under theflange of the screw 150 head.

Shown best in FIG. 3, a bottom portion of the closed perimeter ofterminal frame 110 is defined by a base wall 122 that extends betweenand connects the side walls 114, 115 to each other. In this embodiment,the base wall 122 has multiple segments or portions that are connectedor joined together to cumulatively define the base wall 122. Base wall122 includes an angled base wall portion 124 that extends from the lip120 and an upright base wall portion 125 that extends from the lip 121.Angled base wall portion 124 extends at approximately a 45-degreedownward angle with respect to a flat upper surface of lip 120. Uprightbase wall portion 125 extends at approximately a 90-degree downwardangle with respect to a flat upper surface of lip 121. The angled andupright base wall portions 124, 125 define an approximately 45-degreeangle therebetween and converge directly under the longitudinal axis ofscrew 150.

Referring again to FIGS. 2 and 3, in this embodiment, the blade 130extends continuously from the end of angled base wall portion 124. Thetop portion of blade 130 and the bottom portion of upright base wallportion 125 overlap each other or sit in face-to-face communication atsuch portions. An aperture 132 extends through the top portion of blade130. Finger 128 extends continuously from the end of upright base wallportion 125, through the aperture 132, and includes a bent end thatengages an outwardly facing surface of the blade 130. In thisembodiment, the bent end of finger 128 bends upwardly, toward theterminal frame 110 so that the upright base wall portion 125 and thefinger 128 define a J-shaped cross-section. In other embodiments, finger128 has no discernable bent end or is bent toward some other direction,for example, downwardly, forward, rearward, or otherwise, depending onthe particular end-use configuration of the screw terminal 100.

Shown best in FIG. 2, blade 130 extends as a planar strip of materialfrom the terminal frame 110. Blade 130 includes opposing rectangularprojections that extend from front and back edges of the blade 130 andare received in corresponding grooves of frontward and rearward facingwalls of the housing 10. Regardless of the particular configuration ofblade 130, it is configured for receipt into a conductive socket orother electrical component of the end-use device to electrically couplethe wire 8 to an electrical circuit of such device, the wire 8 beingclamped in the screw terminal 100 with the nut 160. Therefore, althoughblade 130 includes not only planar strips of conductive material, butalso, for example, conductive pins, conductive posts, and/or otherconductive hardware depending on the particular end use configuration ofthe block 5 and/or receptacle 6.

Referring again to FIGS. 2 and 3, preferably the entire screw terminal100, with the exception of screw 150 and nut 160, is made from a singlecontinuous piece of electrically conductive material. In suchconfiguration, the screw terminal 100 may start from a single piece ofmaterial that is, for example, punched, blanked, and then braked orotherwise bent to form the entire assemblage of screw terminal 100.Accordingly, screw terminal 100 may be formed from generally flatmaterial blanks that have the blade 130 at one end and the finger 128 atthe other end. The material that will form the angled base wall portion124, lip 120, side wall 114 and tab 116, upper wall 112, side wall 115and tab 117, lip 121, and base wall upright portion 125 extends betweenthe blade 130 and finger 128. Such material is then bent at respectivelocations along its length to create the corners defined between thevarious segments in order to arrive at the unitary screw terminal 100 asillustrated, with the bottom wall 122 joining the bottoms of the sidewalls 114 and 115 together to define the closed perimeter of terminalframe 110 that restricts rotation of nut 160 while allowing the nut 160to travel vertically therethrough.

Referring now to FIGS. 1 and 4, nut 160 has a generally rectangularperimeter shape and defines a tallness, thickness, or height dimension“H” which is shown in FIG. 4. In this embodiment, height “H” is greaterthan a height dimension of opening 18 of the block housing 10. Bestshown in FIG. 1, referring to the neutral “N” and ground “G” associatedscrew terminals 100, such screw terminals 100 have nuts 160 that are ina closed position. The nuts 160 in the closed position are screwed allthe way up against the upper wall 112 of the terminal frame 110. In thisposition, since the height “H” of nut 160 is greater than the height ofopening 18, the opening 18 is completely blocked by the nut 160 frominside of the screw terminal 100, fully preventing the wire 8 from beinginserted into the screw terminal 100 in any way. Referring to the line“L” associated screw terminal 100, in this screw terminal 100, the nut160 is in an open position in which it is spaced from the upper wall 112of the terminal frame 110. When the nut 160 is in such an open position,a passage is defined through the opening 18 of the housing 10, above thenut 160, and into the inner space of the terminal frame 110. Wire 8 canbe inserted into the screw terminal 100 when the nut 160 is in the openposition, such as that associated with line “L”, as shown in FIG. 1.

In other embodiments, the height “H” of nut 160 is not large enough tocompletely cover the opening 18. However, in such embodiments, it ispreferred that any gap which is defined between the edges of opening 18and nut 160, when the nut is in a closed position, is too small for thewire 8 to fit into. This may reduce the likelihood of the wire 8 beinginstalled improperly into the screw terminal 100, with the wire 8 beingon the wrong side of the nut 160.

Referring now to FIG. 4, in this embodiment, nut 160 includes a top wallthat has an irregular surface 162. The irregular surface 162 of this topwall is in the form of multiple ridges 165 that extend parallel to eachother. A direction of extension of the ridges 165 is orthogonal to thelongitudinal axis of the wire 8, so that the ridges 165 engage the outercircumferential surface of the wire 8 in a crosswise manner.

Ridges 165 are configured to create transversely extending localizeddeformations in the wire 8. This increases the surface area of theinterface between the wire 8 and nut 160 and provides a wavy or toothedmechanical interlock therebetween. Although the ridges 165 can deformthe wire 8, the top surfaces of ridges 165 are blunt enough to preventthem from shearing through the wire 8 when clamping the wire 8 into thescrew terminal 100.

Still referring to FIG. 4, in this embodiment, the ridges 165 have flatsurfaces and are defined between pairs of adjacent grooves 172. Thegrooves 172 of the illustrated embodiment have flat bottom walls. Eachgroove 172 includes a pair of slanted side walls that extend from thegroove bottom wall, away from each other, and connect the bottom wall tothe adjacent ridges 165 on opposing sides of the groove 172. Ridges 165of this embodiment are about half as wide as the bottom walls of thegrooves 172. In one embodiment, bottom walls 172 are about 0.010 inch toabout 0.020 inch wide, preferably about 0.015 inch wide and ridges 165are about 0.006 inch to about 0.012 inch wide, preferably about 0.008inch wide. The depth of the grooves 172 can be about the same as thewidth of the flat bottom walls of the grooves 172, optionally less deep,for example, about 0.006 inch in depth. Of course, irregular surface 162in some embodiments has other configurations besides ridges 165 andgrooves 172. For example, the irregular surface 162 can be defined byknurling, bumps, and/or other surface irregularities which may enhancethe ability of the screw terminal 100 to hold wire 8 without shearingit.

Variations and modifications of the foregoing are within the scope ofthe present invention. It is understood that the invention disclosed anddefined herein extends to all alternative combinations of two or more ofthe individual features mentioned or evident from the text and/ordrawings. All of these different combinations constitute variousalternative aspects of the present invention. The embodiments describedherein explain the best modes known for practicing the invention andwill enable others skilled in the art to utilize the invention. Theclaims are to be construed to include alternative embodiments to theextent permitted by the prior art.

Various features of the invention are set forth in the following claims.

1. An electrical screw terminal, comprising: a conductive blade forconnecting the electrical screw terminal to a receptacle that isprovided in an electrical circuit; a terminal frame connected to theblade and having a closed perimeter with an inner space defined withinthe closed perimeter, the closed perimeter of the terminal frame definedat least in part by; an upper wall; a pair of side walls extending fromthe upper wall; and a base wall joining the side walls to each other; ascrew extending into the inner space of the terminal frame and beingrotatable from outside of the terminal frame; a captured nut housed inthe inner space of the terminal frame and engaging the screw such thatthe captured nut moves linearly along the screw when the screw isrotated; and wherein the side walls restrict rotation of the capturednut and are maintained at a constant distance from each other atopposing ends thereof by the upper and base walls, respectively.
 2. Theelectrical screw terminal of claim 1, the base wall further comprising(i) an upright base wall portion that extends generally parallel to theside walls, and (ii) an angled base wall portion that extends generallyangularly with respect to the side walls.
 3. The electrical screwterminal of claim 2, the terminal frame further comprising a pair oflips extending from the side walls into the inner space of the terminalframe, the lips connecting the side walls to the upright and angled basewall portions of the terminal frame
 4. The electrical screw terminal ofclaim 2, further comprising a finger extending between and fixing theupright and angled base wall portions with respect to each other.
 5. Theelectrical screw terminal of claim 4, wherein an aperture extendsthrough at least one of the blade and the base wall and the fingerextends through the aperture so as to prevent sliding between respectivefacing surfaces of the blade and the upright base wall portion.
 6. Theelectrical screw terminal of claim 5, wherein an end of the finger isbent and engages one of the blade and base wall so as to prevent atleast one of (i) separation of the blade and base wall with respect toeach other, and (ii) separation of the upright and angled base wallportions with respect to each other.
 7. The electrical screw terminal ofclaim 5, wherein the finger extends from the upright base wall portionsuch that the upright base wall portion and finger define a J-shapedprofile.
 8. The electrical screw terminal of claim 1, the terminal framefurther comprising a tab extending outwardly from at least one of theside walls.
 9. The electrical screw terminal of claim 8, wherein theterminal frame includes a pair of tabs extending from the pair of sidewalls, respectively, the tabs extending angularly away from each other.10. The electrical screw terminal of claim 1, wherein the captured nutincludes a top wall defining an irregular surface thereof.
 11. Theelectrical screw terminal of claim 10, wherein the top wall of thecaptured nut includes multiple ridges that engage a wire being held inthe electrical screw terminal.
 12. The electrical screw terminal ofclaim 11, wherein the ridges of the captured nut top wall extend in adirection that is generally orthogonal to the wire.
 13. A terminalblock, comprising: an electrical screw terminal that includes a terminalframe having a closed perimeter with an inner space for receiving a wireand a captured nut that is housed within the inner space of the terminalframe and is movable along a screw to clamp the wire against theterminal frame; a housing that is made from an insulating material andat least partially covers the electrical screw terminal and includes anopening that aligns with the inner space of the terminal frame; andwherein the captured nut is movable between (i) an open position inwhich a passage extends through the opening of the housing and into theinner space of the terminal frame allowing the wire to insert throughthe housing and into the terminal frame; and (ii) a closed position inwhich the captured nut extends across substantially the entire openingof the housing, preventing the wire from inserting into the terminalframe.
 14. The terminal block of claim 13, the housing furthercomprising a top wall that engages a head of the screw so as to retainthe screw within the housing.
 15. The terminal block of claim 13,wherein the housing includes multiple interconnected walls defining avoid space therebetween, the housing further comprising a ledgeextending from at least one of the walls and into the void space, theledge engaging the terminal frame of the screw terminal so as to retainthe screw terminal within the housing.
 16. The terminal block of claim15, the terminal frame of the screw terminal further comprising at leastone tab extending therefrom, the tab engaging the ledge of the housingso that the ledge retains the screw terminal within the housing.